1. Field of the Invention
The present invention generally relates to a method for grouping wireless devices and an apparatus thereof, in particular, to a method for grouping proximal wireless devices in consideration of space allocations thereof and an apparatus thereof.
2. Description of Related Art
The demands to location awareness services and location-based services have been increasing along with the widespread of wireless Internet devices, such as notebook computers, personal digital assistants (PDAs) etc. For example, when a wireless device needs to print a document, this document is automatically transmitted to a nearby printer to be printed, and when the wireless device has a projection task, the data to be projected is also automatically transmitted to a nearby projector. In other words, by grouping proximal wireless devices, the wireless device is automatically connected to those service providing devices within the same group, and accordingly, the wireless device can communicate with other nearby wireless devices. As described above, a mechanism for grouping proximal wireless devices so that users of the same group can interact with each other efficiently is an important issue in wireless communication application.
Three methods for grouping proximal wireless devices are usually used in today's wireless communication environment. FIG. 1 illustrates the first conventional method for grouping proximal wireless devices. Referring to FIG. 1, the first method is provided to group wireless devices based on the access points (APs) connecting to the communication network, namely, those wireless devices which connect to the communication network through the same AP are considered proximal wireless devices. As shown in FIG. 1, the wireless devices W1˜W5 connect to the Internet through AP1, thus, the wireless devices W1˜W5 are considered proximal wireless devices and are grouped together. While the wireless devices W6˜W9 connect to the communication network through AP2, so the wireless devices W6˜W9 are put into another group.
FIG. 2 illustrates the second conventional method for grouping proximal wireless devices. Referring to FIG. 2, the second method is to group wireless devices based on the signals received by the wireless devices from APs, namely, those wireless devices having their strongest signals received from the same AP are considered proximal wireless devices. As shown in FIG. 2, the signal strength of the received signals by the wireless devices W1˜W4 from AP1 are within the same range, so that the wireless devices W1˜W4 are considered proximal wireless devices and are grouped together as Group 1. While the signal strength of the received signals by the wireless devices W6˜W9 are within the same range from AP2, so the wireless devices W6˜W9 are put into another group as Group 2. As indicated in dot line 210 that the wireless devices are grouped according to the signal strength of the signals received. However, the wireless device W5 receives a stronger signal from the AP2 rather than that from the AP1, and is grouped as one member of the Group 2, instead of the desire to be grouped as the member of Group 1.
According to the third method for grouping wireless devices, the proximity of wireless devices are determined by accurately locating the wireless devices and then calculating the distances between them. The wireless devices can be accurately located through a global positioning system (GPS) or a wireless fidelity (Wi-Fi) positioning appliance, and then whether or not they are proximal wireless devices is determined according to a distance formula. However, since space allocations of the wireless devices are not considered in the three methods described above, the grouping result provided may not be satisfactory.
For example, FIG. 3 is a diagram illustrating the space allocations of wireless devices. Referring to FIG. 3, with the consideration of space allocation, the members X1˜X6 (i.e. wireless devices) in the conference room should be in the same group, and this group should be separated from the members X7˜X9 (i.e. wireless devices) outside of the conference room. However, the member X6 in the conference room and the member X7 out of the conference room may be put in the same group if the members are simply grouped based on the same AP they use for connecting to the communication network or the strength of the signals they receive from the same AP. Besides, even though proximal wireless devices can be determined accurately through accurate positioning, members in or out of the conference room cannot be distinguished effectively without adopting a map regarding the space allocation thereof. Besides, a radio map has to be established in advance through sampling point calculation and then the accurate locations of the wireless devices have to be calculated according to the signals received by the wireless devices if a Wi-Fi positioning appliance is used; thus, the complexity of actual operation is increased.
An improved accurate positioning method is disclosed in an article titled “WLAN location determination via clustering and probability distribution”. According to this article, sampling points are established during an offline phase and those sampling points of the APs having the same Q strongest wireless signals are put in one group (sampling group). Thus, during a location determination phase, a suitable sampling group at a particular sampling point can be located based on only those APs having the Q strongest wireless signals so that the possible range of the user location is reduced.
A group notification system and associated method that allow particular activities to be executed based on the group dynamics are disclosed in U.S. Pat. No. 6,529,136. The group dynamics may be the proximity and direction of movement of group members or distances between groups.
A system of wireless proximity awareness and an associated method are disclosed in U.S. Pat. No. 7,035,618. When a mobile device is connected to a particular wireless tower which uses, for example, the global system for mobile communications (GSM) and a member in the friend list of the mobile device is also connected to the same wireless tower or to a proximal wireless tower which uses a different system, for example, a code division multiple access (CDMA) system, an event is triggered to notify these two wireless mobile devices that they are proximal. Similar to the method described above, this method cannot provide an effective grouping which conforms to the space allocation of the wireless devices.
A wireless network and an associated method for determining nearest wireless device are disclosed in U.S. Patent No. 20050227724, wherein a nearest wireless device is determined according to signal strengths measured between wireless devices and APs. For example, a notebook computer determines whether it is closer to a printer A or a printer B by measuring the signal strengths of the wireless network. The present disclosure is focused at locating a nearest signal wireless device or service device, but does not provide a method for grouping proximal wireless devices.